1. Field of the Invention
The present invention relates generally to a ventilation system used in respiratory diagnostic imaging. Specifically, the present invention relates to devices used in the diagnostic imaging of a patient's pulmonary function, and more particularly, is directed to a disposable inhalation adaptor to be used in conjunction with standard, portable, ventilation apparatus. More specifically, the invention involves a hand-held ventilation system which delivers oxygen as well as the appropriate dose of Xenon-133 gas to the patient without contaminating the surrounding area. The claimed ventilation system is particularly designed for use with patients who cannot breathe on their own or who cannot cooperate with the standard respiratory diagnostic imaging apparatus.
2. Background Information
Performing ventilation imaging on a patient requires the patient to inhale radioactive material. The images of the distribution of the radioactive material provide a means for assessing the anatomy and physiology of the lung through diagnostic testing.
Respiratory diagnostic imaging is performed to determine the functioning; i.e., inhalation and exhalation capability, of the lungs of a patient. In assessing whether a patient's lungs are functioning, the physician first will order a regular chest X-ray which will provide an image of the anatomy of the lung of a particular patient. Then, the physician will order a radioactive ventilation scan and compare the X-ray and imaging of the lungs to determine which portions of the lungs are functioning and not functioning. The ventilation images are usually compared to radioactive perfusion images to assess blood flow in relation to ventilation: gas delivery and gas exchange.
Standard ventilation systems for respiratory diagnostic imaging have been developed and are presently used in patients who are able to cooperate with their use. These systems utilize a mask which straps onto the face of the patient covering the nose and mouth. The mask has one opening through which the Xenon-133 gas is introduced and through which the gas is exhausted into a radioactive trapping device. The patient inhales the Xenon-133 into the lungs and a gamma camera is used to take an image of the Xenon-133 which is present in the lungs.
There are, however, patients who require respiratory diagnostic imaging but who cannot be imaged using the standard ventilation systems. These patients include those who are unable to breath on their own and who are on ventilators or patients who can breath on their own but cannot cooperate with the standard ventilation imaging techniques, such as a pediatric patient or a sedated or comatose patient.
The ventilation system for respiratory diagnostic imaging of the present invention can be used on intubated patients by attachment to their tracheal tubes or can be used on patients who do not have tracheotomies but who cannot breathe on their own by attachment to a mask which covers the nose and mouth of the patient.
Additionally, the ventilation system of the present invention reduces the amount of "dead space" from the inhalation adaptor forward into the patient and the patient's airways. The "dead space" refers to the amount of space including either tubing or human airways which is not involved or participating in the actual exchange of oxygen with the blood. If the "dead space" is too large, then there is poor oxygenation of the patient and eventually respiratory compromise. At present, standard imaging systems have extensive tubing which results in large amounts of "dead space" providing unacceptable ventilation support. The present system overcomes these disadvantages of the standard imaging systems as a result of the use of a one-way valve in the present system which reduces the dead space.
Thus, a need exists for a ventilation system for diagnostic imaging which can be used to perform respiratory diagnostic imaging on patients who are on ventilators or who cannot cooperate with standard ventilation imaging techniques. Further, it is necessary that this apparatus provide an enclosed system to deliver radioactive gas and recover it after delivery without any contamination to the surrounding area and personnel performing the imaging.